This invention relates to a machine for producing ice creams, particularly stick-supported ice creams, such as `icicles` or ice dollies, sorbets and the like.
An ice cream machine of this type generally has a number of moulds arranged in parallel rows, which are caused to advance intermittently through a freezing tank by means of a pull chain. At an initial part of said freezing tank, there is provided a dosing means which, at the commencement of a cycle, injects a given quantity of product, in a liquid state, in the molds of each mould row.
Placed at an intermediate location of the freezing tank is a stick-inserting device which is arranged to insert sticks in the moulds of each mould row when the product commences to solidify therein.
At the exit from the freezing tank there are drawing rods which operate, in turn, intermittently under control of a pull chain, to draw the frozen products out of each row of moulds and then release them for delivery to a paper wrapping system.
At present, a stringent need exits for an increased productivity of these machines, which productivity is measured in terms of number of shots per minute, where the term "shot" is intended to mean one advance, or step forward, of the mold-pulling chain, which corresponds to one dosing operation, one stick-inserting operation, one drawing-out operation and one release operation. In particular, the drawing-out operation comprises a one-step advance of the pull chain for the drawing-out rods, one downward movement of a drawing rod and one upward or return movement of same rod.
Thus, to-day's ice cream machines have a productivity limit, in terms of shots per minute, which cannot be exceeded for mechanical reasons, such as inertia of individual parts, the minimum time lengths necessary for the different elements to complete their movement between a shot and the subsequent one, and so on.
In particular, this mechanical limit is imposed mostly, though not exclusively, by the frozen product-drawing-out operation which requires, between one shot and the further one, as mentioned above, a one-step advance of the pull chain for the drawing-out or lifting-up rods, the descent of one said rod for positioning it over a row of moulds containing the frozen products ready for removal, and the ascent of same rod.
On the other hand, it is inconceivable for these machines to be operated near said upper limit which would lead all of their mechanical parts to work under highest stress conditions with the risk of failure being considerably increased. Thus, an effort has been made towards increasing the width of these machines in order to have a greater number of molds per mold row but, in this case too, a given number of molds per mold row cannot be exceeded both in view of the fact that operators controlling operation of the machine on either side thereof are to be enabled to have the centerline zone of the machine within their reach to take measures there, if necessary, and in order to prevent cooled brine from being irregularly distributed inside the tank which would lead to differences in freezing of the products.
There exists, thus, a problem long unsolved in the ice cream machine art, that is to increase productivity of these machines by overcoming the above described mechanical limit.